The standardization of new high-density read only and rewritable optical disks capable of recording large amounts of high-quality video and audio data has been progressing rapidly. The Blu-ray Disc Rewritable (BD-RE) is one example of these new optical disks. As shown in FIG. 1, a BD-RE disk comprises a clamping area, a transition area, a burst cutting area (BCA), a lead-in zone, a data zone, and a lead-out zone.
As shown in FIG. 2, data recorded on the BD-RE disk is organized into a plurality of recording unit blocks (RUBs) each of which corresponds to an ECC block.
In the case where data is recorded as only one RUB, the RUB comprises a run-in area of 2760 channel bits, a physical cluster of 958272 channel bits, and a run-out area of 1104 channel bits. The RUB is followed by a guard 3 area of 540 channel bits.
On the other hand, if data is recorded as a plurality of RUBs with time continuity, one guard 3 area of 540 channel bits is placed after the plurality of RUBs in order to prevent the recorded RUBs from being overwritten by data to be recorded next.
As shown in FIG. 3, 31 recording frames (Frame #0˜Frame #30) are sequentially recorded in the physical cluster area and the group of 31 recording frames is recorded repeatedly 16 times. The 31 recording frames (Frame #0˜Frame #30) are associated with 7 different frame syncs (Frame Sync #0˜Frame Sync #6) in a predefined order.
As shown in FIG. 4, the run-out area comprises a post-amble of 564 channel bits and a guard 2 area of 540 channel bits. In the guard 2 area, a pattern of 20 channel bits is recorded 27 times repeatedly in order that the end of the RUB may be detected. The post-amble includes a sync of 30 channel bits (Sync 3).
As shown, the run-in area comprises a guard 1 area of 1100 channel bits and a pre-amble of 1660 channel bits. In the guard 1 area, a pattern of 20 channel bits is recorded 55 times repeatedly in order that the beginning of the RUB may be detected. The pre-amble includes two syncs (Sync 1 and Sync 2) each having 30 channel bits.
As shown in FIG. 5, the physical cluster of the BD-RE includes physical address information for random access to the RUB, i.e., 16 address unit numbers (AUN 0˜AUN 15). The address information is modulated and encoded together with A/V data and recorded in the physical cluster in a distributive manner.
As described with reference to FIG. 3, 31 frames (Frame #0˜Frame #30) of each address unit number (AUN) are assigned 7 frame syncs in a predetermined order. The recording frame number of a targeted recording location can be identified by a combination of the frame sync detected at the targeted recording location and 4 successive frame syncs detected just before the targeted recording location as shown in FIG. 5.
For example, if the frame sync ‘FS 0’ included in Frame #0 of AUN 1 is detected after ‘FS 6’, ‘FS 4’, ‘FS 4’, and ‘FS 2’ included in Frame #27, Frame #28, Frame #29, and Frame #30 of AUN 0 are detected successively, the current recording location (i.e., the targeted recording location) is identified as Frame #0 based on the information.
In the BD-RE, ‘FS 0’ is also recorded in Sync 3 of the run-out area as shown in FIG. 5. Therefore, if Frames #27˜#30 of the last AUN (AUN 15) corresponding ‘FS 6’, ‘FS 4’, ‘FS 4’, and ‘FS 2’ respectively are detected and then ‘FS 0’ of Sync 3 is detected, the recording location at which ‘FS 0’ is detected may be misidentified as the first recording frame (Frame #0) of the physical cluster. An effective method for solving this problem is not yet available.
The standardization for high-density read-only optical disks such as the Blu-ray ROM (BD-ROM) is under way. A recording format that enables determination of recording locations on the BD-ROM needs to be defined. If the recording format of the BD-RE is applied to the BD-ROM, the aforementioned problem of incorrect identification of recording locations remains unsolved. Therefore, an effective method of correctly determining a recording location on a BD-ROM disk as well as a BD-RE disk needs to be developed.